Disney Legend Frank Thomas, one of Walt’s esteemed Nine Old Men, started his animation career with Disney in 1934 and remained on staff until 1978. In 1942, however he left the Company to enlist in the Air Force and didn’t return until 1946. But even World War II couldn’t keep Frank away from animation. For most of the conflict, he made animated training films for the military in the First Motion Picture Unit of the Air Force.